With certain integrated circuit devices, such as radio frequency (RF) devices, impedance matching to an antenna is required to achieve the desired performance. For instance, a tuning process is required for RF identification devices (RFID) to achieve the desired operating distance. However, due to typical underlying manufacturing processes of semiconductor wafers, a certain variation and consequently a deviation in the RF-output impedance of the device is encountered. To match the antenna impedance, discrete passive components are required. During test processes for such RF devices, different results can be obtained depending on the variance of those discrete components. A further optimization to match the antenna impedance, such as would be required for RFID devices, does not take place during the component manufacturing processes.
With known processes, such RF components typically are not tuned until they are mounted on a printed circuit board (PCB) as part of a larger system. Tuning processes at a system or board level is difficult and expensive. For instance, in systems on PCBs a tunable capacitor (for example, cermet trimmer) is mounted on the PCB for this purpose. Alternatively, when manufacturing devices such as RF-IDs, the wafer manufacturing process is kept in a narrow process window to keep the variations as low as possible. Unfortunately, this also adds complexity and cost to manufacturing processes.
For these and other reasons, there is a need for the present invention.